Close coupled single module aftertreatment system

ABSTRACT

An aftertreatment system includes a filtration and reduction unit. The filtration and reduction unit comprises a housing defining an internal volume. A filter is disposed in the internal volume and is configured to substantially remove particulates from the exhaust gas. A selective catalytic reduction system is disposed in the internal volume downstream of the filter and is configured to selectively reduce a portion of the exhaust gas. A first catalyst is formulated to oxidize at least a portion of the exhaust gas. An intake pipe is disposed upstream of the filtration and reduction unit and configured to communicate the exhaust gas o the filtration and reduction unit. The first catalyst is disposed in the intake pipe. An exhaust pipe is disposed downstream of the filtration and reduction unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/539,954, filed Jun. 26, 2017, which is a National stage of PCTApplication No. PCT/US2015/067324, filed Dec. 22, 2015, which claimspriority to and the benefit of U.S. Provisional Application No.62/098,653, filed Dec. 31, 2014 and entitled “Close Coupled SingleModule Aftertreatment System.” The contents of all 3 applications areherein incorporated by reference in their entirety and for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to exhaust aftertreatmentsystems for use with internal combustion (IC) engines.

BACKGROUND

During the combustion process in an IC engine (e.g., a diesel-poweredengine), sulfur is concurrently formed with carbon monoxide (CO) andhydrocarbons (HC) as various sulfur oxides (SO_(x)). Typically, 97-99%of the total amount of SO_(x) present in exhaust gas includes sulfurdioxide (SO₂) and 1-3% includes sulfur trioxide (SO₃). Thus, fuels withhigher sulfur content tend to produce higher amounts of SO₃. Forexample, fuel with sulfur content of 1000 ppm may form approximately 1-3ppm SO₃.

Exhaust aftertreatment systems are used to receive and treat exhaust gasgenerated by IC engines. Conventional exhaust gas aftertreatment systemsinclude any of several different components to reduce the levels ofharmful exhaust emissions present in exhaust gas. For example, certainexhaust aftertreatment systems for diesel-powered IC engines can includea selective catalytic reduction (SCR) catalyst to convert NO_(x) (NO andNO₂ in some fraction) into harmless nitrogen gas (N₂) and water vapor(H₂O) in the presence of ammonia (NH₃). Generally in such conventionalaftertreatment systems, an exhaust reductant, (e.g., a diesel exhaustfluid such as urea) is injected into the aftertreatment system toprovide a source of ammonia, and mixed with the exhaust gas to partiallyreduce the SO_(x) and/or the NO_(x) gases. The reduction byproducts ofthe exhaust gas are then fluidically communicated to the catalystincluded in the SCR aftertreatment system to decompose substantially allof the SO_(x) and NO_(x) gases into relatively harmless byproducts whichare expelled out of such conventional SCR aftertreatment systems.

Conventional aftertreatment systems can also include one or morecatalysts for pretreatment and/or post treatment of the exhaust gas. Forexample, some conventional aftertreatment systems for treating dieselexhaust gas can also include a diesel oxidation catalyst, and/or anammonium oxidation catalyst. Other components can also include a filter.Each of these components is disposed in conventional aftertreatmentsystems within the length constraints of the aftertreatment systemimposed by the dimensions (e.g., length) of the machine generating theexhaust gas. While it is desirable that the residence time of theexhaust gas in the SCR system is maximized, length constraints of theaftertreatment can limit the dimensions of the components of theaftertreatment system.

SUMMARY

Embodiments described herein relate generally to exhaust aftertreatmentsystems for use with IC engines, and in particular to exhaustaftertreatment systems that include a first oxidation catalyst disposedin an intake pipe of the aftertreatment systems.

In a first set of embodiments, an aftertreatment system includes afiltration and reduction unit. The filtration and reduction unitcomprises a housing defining an internal volume. A filter is disposed inthe internal volume and is configured to substantially removeparticulates from the exhaust gas. A selective catalytic reductionsystem is disposed in the internal volume downstream of the filter andis configured to selectively reduce a portion of the exhaust gas. Afirst catalyst is formulated to oxidize at least a portion of theexhaust gas. An intake pipe is disposed upstream of the filtration andreduction unit and configured to communicate the exhaust gas o thefiltration and reduction unit. The first catalyst is disposed in theintake pipe. An exhaust pipe is disposed downstream of the filtrationand reduction unit.

In particular embodiments, the first catalyst can include a dieseloxidation catalyst. In other embodiments, the intake pipe comprises afirst intake pipe and a second intake pipe such that the first catalystis disposed in each of the first intake pipe and the second intake pipe.The aftertreatment system may also include a second catalyst formulatedto oxidize an exhaust reductant. The second catalyst can include anammonium oxidation catalyst. The second catalyst can be disposed in theexhaust pipe.

In another set of embodiments, an aftertreatment system comprises ahousing including an inlet, an outlet and defining an internal volume.An intake pipe is fluidly coupled to the inlet. A SCR system ispositioned within the internal volume defined by the housing.Furthermore, a first catalyst is positioned within the intake pipe.

In yet another set of embodiments, a method for increasing a spaceavailable within a housing of an aftertreatment system which defines aninternal volume comprises positioning a selective catalytic reductionsystem within the internal volume defined by the housing. An intake pipeis fluidly coupled to an inlet of the housing. Furthermore, a firstcatalyst is positioned within the intake pipe.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several implementations in accordance withthe disclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 is a schematic block diagram of an aftertreatment system thatincludes a first catalyst and optionally, a second catalyst, accordingto an embodiment.

FIG. 2 is a side cross-section view of an aftertreatment system,according to another embodiment.

FIG. 3 is a side cross-section view of an aftertreatment system,according to yet another embodiment.

FIG. 4 is a schematic flow diagram of an example method for increasing aspace available within an internal volume defined by a housing of anaftertreatment system, for housing various aftertreatment componentstherewithin.

Reference is made to the accompanying drawings throughout the followingdetailed description. In the drawings, similar symbols typicallyidentify similar components, unless context dictates otherwise. Theillustrative implementations described in the detailed description,drawings, and claims are not meant to be limiting. Other implementationsmay be utilized, and other changes may be made, without departing fromthe spirit or scope of the subject matter presented here. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, and designed in a wide variety ofdifferent configurations, all of which are explicitly contemplated andmade part of this disclosure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Embodiments described herein relate generally to exhaust aftertreatmentsystems for use with IC engines, and in particular to exhaustaftertreatment systems that include an oxidation catalyst disposed in anintake pipe of the aftertreatment system. Embodiments described hereinmay provide certain benefits including, for example: (1) disposing afirst oxidation catalyst in an intake pipe thereby, allowing more spacefor an SCR system, filter, and/or a body mixer to be disposed within theaftertreatment system; (2) disposing a second oxidation catalyst in anexhaust pipe thereby providing even more space for disposing the SCRsystem, filter, and/or the body mixer within the aftertreatment system;(3) allowing increase in the dimensions (e.g., length and/or width) ofthe SCR system and/or body mixer relative to conventional aftertreatmentsystems without increasing the overall length of the aftertreatmentsystem; (4) increasing retention time of the exhaust gas or exhaustgas/exhaust reductant mixture within the aftertreatment system which maylead to better mixing, increased efficiency of the SCR catalysts, highertemperatures, less deposits, and/or lower backpressure; (5) reducingheat loss, thereby reducing the amount and cost of insulation; and (6)providing better distribution of particulate matter (e.g., soot)entrained in the exhaust gas flowing through the aftertreatment system.

FIG. 1 shows an aftertreatment system 100 for treating an exhaust gas(e.g., a diesel exhaust gas) produced by an IC engine (e.g., a dieselengine). The aftertreatment system 100 includes an intake pipe 102, afirst catalyst 110, a filtration and reduction unit 118 which includes afilter 120 and a selective catalytic reduction (SCR) system 150, and anexhaust pipe 180. The aftertreatment system 100 can optionally, alsoinclude a second catalyst 170.

The intake pipe 102 is disposed upstream of the filtration and reductionunit 118. The intake pipe 102 is configured to receive an exhaust gas(e.g., a diesel exhaust gas) from an IC engine (e.g., a diesel engine)and communicate the exhaust gas to the filtration and reduction unit118. The intake pipe 102 can be made from a strong, rigid, heat and/orcorrosion resistant material such as, metals (e.g., stainless steel,aluminum, alloys, etc.), ceramics, any other suitable material or acombination thereof. The intake pipe 102 can have any suitablecross-section, for example, a circular, square, rectangular, polygonal,oval, or any other suitable cross-section.

The first catalyst 110, for example a first oxidation catalyst, isformulated to oxidize at least a portion of the exhaust gas flowingthrough the first catalyst 120. For example, in some embodiments inwhich the exhaust gas is a diesel exhaust gas, the first catalyst 120can include a diesel oxidation catalyst. The diesel oxidation catalystcan be formulated to oxidize carbon monoxide, hydrocarbons, and/orparticulate matter included in the exhaust gas flow. Moreover, thediesel oxidation catalyst can be formulated to have a low light-offtemperature and/or a high tolerance to sulfur (e.g., SO_(x) gasesincluded in the exhaust gas). Suitable diesel oxidation catalysts caninclude, for example, platinum, palladium, aluminum oxide, or acombination thereof.

The first catalyst 110 is disposed within a flow path defined by theintake pipe 102. In one embodiment, the first catalyst 110 can befixedly disposed in the intake pipe 102. In other embodiments, the firstcatalyst 110 can be removably disposed in the intake pipe 102, forexample, to allow replacement of the first catalyst 110 withoutreplacing the intake pipe 102. In some embodiments, the intake pipe 102can divide or otherwise split into a plurality of intake pipes each ofwhich are in fluidic communication with the filtration and reductionunit 118. In other words, the intake pipe 102 can divide the flow ofexhaust gas into a plurality of portions which are then delivered to thefiltration and reduction unit 118. In such embodiments, the firstcatalyst 110 can be disposed in each of the plurality of intake pipesfeeding into the filtration and reduction unit 118. For example, in oneembodiment, the intake pipe 102 can divide into a first intake pipe anda second intake pipe and the first catalyst 110 can be disposed in eachof the first intake pipe and the second intake pipe.

A plurality of temperature sensors can also be disposed in the intakepipe 102 to measure a temperature of the exhaust gas at variouslocations within the intake pipe (e.g., before contacting the firstcatalyst 110, and/or after flowing through the first catalyst 110).

The filtration and reduction unit 118 includes a housing (not shown)defining an internal volume. The housing can be formed from any suitablematerial, for example, metals or ceramics. The housing can define anysuitable cross-section, for example, a circular, square, rectangular,polygonal, elliptical, or any other suitable cross-section.

The filter 120 is disposed within the internal volume defined by thehousing. The filter 120 is configured to receive the flow of the exhaustgas (e.g., a diesel exhaust gas) from the intake pipe 102. The filter120 can include any suitable filter (e.g., a diesel particulate filter)configured to filter and remove any particulates entrained within theexhaust gas flow, and prevent such particulates from entering the SCRsystem 150. Such particles can include, for example, dust, soot, organicparticles, crystals, or any other solid particulates present in theexhaust gas. The filter 120 can include a filter housing made of astrong and rigid material such as, for example, high densitypolypropylene (HDPP) which can define an internal volume to house afilter element. Any suitable filter element can be used such as, forexample, a cotton filter element, an acrylonitrile butadiene styrene(ABS) filter element, any other suitable filter element or a combinationthereof. The filter element can have any suitable pore size, forexample, about 10 microns, about 5 microns, or about 1 micron.

One or more temperature sensors can be disposed in, or otherwiseproximate to the filter 120 (e.g., at an entrance of the filter 120) tomeasure the temperature of the exhaust gas. Furthermore, a pressuresensor can also be disposed on the filter 120 to measure any changes ina pressure of the exhaust gas flowing through the filter 120. In someembodiments, the pressure sensor can include a differential pressuresensor positioned across the filter 120 to determine a differentialpressure thereacross. In other embodiments, the pressure sensor caninclude a first pressure sensor positioned upstream of the filter 120and a second pressure sensor positioned downstream of the filter 120.The first pressure sensor measures a first pressure upstream of thefilter 120, and the second pressure sensor measures a second pressuredownstream of the filter 120. The difference between the first pressureand the second pressure represents the pressure drop across the filter120. Change in pressure of the exhaust gas or the pressure drop acrossthe filter 120 can, for example, provide information on the amount ofparticulate trapped within the filter 110, and/or the remaining life ofthe filter 110. For example, a change in exhaust gas pressure above apredetermined threshold can indicate that the filter 120 issubstantially clogged and should be replaced.

In some embodiments, a body mixer (not shown) can also be included inthe aftertreatment system 100. In such embodiments, the body mixer canbe disposed within the internal volume defined by the housing. The bodymixer can be disposed downstream of the filter 120 and upstream of theSCR system 150, and configured to fluidically couple the filter 120 tothe SCR system 150. The body mixer can include a body mixer housingdefining an internal volume. An injection port can be disposed on asidewall of the body mixer housing and configured to communicate anexhaust reductant into the body mixer. In some embodiments, the exhaustgas can include a diesel exhaust gas and the exhaust reductant caninclude a diesel exhaust fluid. The diesel exhaust fluid can include,urea, an aqueous solution of urea, or any other fluid that includesammonia, by products, or any other diesel exhaust fluid as is known inthe arts (e.g., the diesel exhaust fluid marketed under the nameADBLUE®.

The body mixer can be structured to allow efficient mixing of theexhaust reductant with the exhaust gas before communicating the exhaustgas into the SCR system 150. The body mixer can include any suitablestructures such as, for example, passageways, bluffs, vanes, partitionwalls, or any other features or structures to facilitate the mixing ofthe exhaust reductant with the exhaust gas.

The SCR system 150 is disposed within the internal volume defined by thehousing of the filtration and reduction unit 118. The SCR system 150 isdisposed downstream of the filter 120 and is configured to treat anexhaust gas (e.g., a diesel exhaust gas) flowing through the SCR system150. The SCR system 150 is configured to selectively reduce a portion ofthe exhaust gas. For example, the exhaust reductant can react with theexhaust gas to at least partially reduce one or more components of thegas (e.g., SOx and NOx), or facilitate reduction of the one or morecomponents in the presence of one or more catalysts included the SCRsystem 150. One or more temperature sensors can also be disposed in theSCR system 150 to measure a temperature of the exhaust gas.

The SCR system 150 includes one or more catalysts formulated toselectively reduce the exhaust gas. Any suitable catalyst can be usedsuch as, for example, platinum, palladium, rhodium, cerium, iron,manganese, copper, vanadium based catalyst, any other suitable catalyst,or a combination thereof. The catalyst can be disposed on a suitablesubstrate such as, for example, a ceramic (e.g., cordierite) or metallic(e.g., kanthal) monolith core which can, for example, define a honeycombstructure. A washcoat can also be used as a carrier material for thecatalysts. Such washcoat materials can include, for example, aluminumoxide, titanium dioxide, silicon dioxide, any other suitable washcoatmaterial, or a combination thereof. The exhaust gas (e.g., dieselexhaust gas) can flow over and about the catalyst such that any SOx orNOx gases included in the exhaust gas are further reduced to yield anexhaust gas which is substantially free of carbon monoxide, SOx and NOxgases.

The exhaust pipe 180 is disposed downstream of the filtration andreduction unit 118. The exhaust pipe 180 can be formed fromsubstantially the same materials as the intake pipe 102. The exhaustpipe 180 is configured to receive the treated exhaust gas (or otherwisemixture of treated exhaust gas and any excess exhaust reductant (e.g.,urea) or its byproducts (e.g., ammonia)), and deliver it to the externalenvironment. One or more sensors can also be disposed in the exhaustpipe 180 to measure a concentration of one or more components of theexhaust gas. For example, in some embodiments in which the exhaust gasincludes a diesel exhaust gas, NOx sensors, SOx sensors, and/or exhaustreductant (e.g., ammonia) sensors can be disposed in the exhaust pipe180.

In some embodiments, the aftertreatment system 100 can also include asecond catalyst 170 (e.g., a second oxidation catalyst). In oneembodiment, the second catalyst 170 can be disposed downstream of theSCR system 150 within the internal volume defined by the housing of thefiltration and reduction unit 118, and upstream of the exhaust pipe 180.In other embodiments, the second catalyst 170 can be disposed within theexhaust pipe 180.

The second catalyst 170 can be formulated to oxidize any excess exhaustreductant included in the exhaust gas exiting the SCR system 150. Forexample, the exhaust reductant can be a diesel exhaust fluid (e.g., anaqueous solution of urea as described herein) that provides a source ofammonia for participating in the selective catalytic reduction withinthe SCR system 150. In such embodiments, the second catalyst 170 caninclude an ammonium oxidation catalyst formulated to oxidize ammonia tonitrogen. Suitable catalysts can include platinum, palladium, iridium,ruthenium, silver, metal oxides (e.g., Co₃O₄, MnO₂, V₂O₅, etc.), Ni, Fe,and/or Mn supported on Al₂O₃, CuO/Al₂O₃, Fe₂O₃/Al₂O₃, Fe₂O₃/TiO₂,Fe₂O₃/ZrO₂, zeolites (e.g., mordenite, ferrierite, chabazite) any othersuitable ammonia oxidation catalyst or a combination thereof.

As described herein, the first catalyst 110 is disposed in the intakepipe 102. Furthermore, the second catalyst 170 can also be disposed inthe exhaust pipe 180. This can enable a dimension (e.g., a length) ofthe filtration and reduction unit 118 (e.g., the housing of thefiltration and reduction unit 118, or a length of the filter 120 and/orthe SCR system 150) to be increased without increasing the overalldimension (e.g., length) of the housing of the filtration and reductionunit 118 of the aftertreatment system 100.

The distance between an outlet of the intake pipe (i.e., the end coupledto the housing of the aftertreatment system 100) and an inlet of theexhaust pipe (i.e., the end coupled to the housing of the aftertreatmentsystem 100) defines the length of a body of an aftertreatment system,for example the housing of the filtration and reduction unit 118. Inconventional aftertreatment systems, each component of theaftertreatment system, for example, a first catalyst (e.g., a dieseloxidation catalyst), a filter (e.g., a diesel particulate filter), amixer, an SCR system, and/or the second catalyst (e.g., an ammoniumoxidation catalyst) are disposed between the intake pipe and the exhaustpipe. This creates a limit on the length of the SCR system, the filter,and the body mixer.

In contrast, the aftertreatment system 100 allows for the first catalyst110 to be disposed within the intake pipe 102 and the second catalyst170 to be disposed within the exhaust pipe 180. In this manner, thedistance between the outlet of the intake pipe 102, and the inlet of theexhaust pipe 180 remains the same but now the entire length of thehousing of the filtration and reduction unit 118 is available fordisposing the filter 120, body mixer and the SCR system 150. This,enables a length of the filtration and reduction unit 118 (i.e., thelength of the SCR system 150, the body mixer, and/or the filter 110) tobe increased relative to conventional aftertreatment systems.

The increased length can increase the residence time of the exhaust gas(or otherwise a mixture of the exhaust gas and the exhaust reductant)within the filter 110, the body mixer, and/or the SCR system 150. Theincreased residence time can provide several benefits, for example, moreefficient mixing of the exhaust reductant with the exhaust gas, moreefficient reduction of the SOx and/or NOx gases included in the exhaustgas (e.g., diesel exhaust gas), increased temperature, and/or reducedbackpressure. Furthermore, positioning the first catalyst 110 in theintake pipe 102 can prevent heat loss by allowing utilization of theheat of the oxidation reaction taking place within or on the firstcatalyst 110 (e.g., within pores defined by the first catalyst 110 or ona surface of the first catalyst 110).

FIG. 2 is side cross-sectional view of an aftertreatment system 200which can be used for treating an exhaust gas (e.g., a diesel exhaustgas) produced by an IC engine (e.g., a diesel engine). Theaftertreatment system 200 includes an intake pipe 202, a first catalyst210, a filtration and reduction unit 218 that includes a filter 220, abody mixer 230 and a SCR system 250, a second catalyst 270, and anexhaust pipe 280.

The intake pipe 202 is disposed upstream of the filtration and reductionunit 218, and is configured to receive an exhaust gas (e.g., a dieselexhaust gas) from an IC engine (e.g., a diesel engine) and communicatethe exhaust gas to the filter 220. The intake pipe 202 can be made froma strong, rigid, heat and/or corrosion resistant material such as,metals (e.g., stainless steel, aluminum, alloys, etc.), ceramics, anyother suitable material or a combination thereof. The intake pipe 202can have any suitable cross-section, for example, a circular, square,rectangular, polygonal, oval, or any other suitable cross-section.

The first catalyst 210 is formulated to oxidize at least a portion ofthe exhaust gas flowing through the first catalyst 210. For example, insome embodiments in which the exhaust gas is a diesel exhaust gas, thefirst catalyst 210 can include a diesel oxidation catalyst. The dieseloxidation catalyst can be formulated to oxidize carbon monoxide,hydrocarbons, and/or particulate matter included in the exhaust gasflow. Moreover, the diesel oxidation catalyst can be formulated to havelow light-off temperature and high tolerance to sulfur (e.g., SOx gasesincluded in the exhaust gas). Suitable diesel oxidation catalysts caninclude, for example, platinum, palladium, aluminum oxide, or acombination thereof.

As shown in FIG. 2, the first catalyst 210 is disposed within a flowpath defined by the intake pipe 202. The first catalyst 210 can befixedly or removably disposed within the flow path, for example, toallow replacement of the first catalyst 210 without replacing the intakepipe 202. A first temperature sensor 216 a is disposed in the intakepipe 202 upstream of the first catalyst 210, and a second temperaturesensor 216 b is also disposed in the intake pipe 202 downstream of thefirst catalyst 210. The first temperature sensor 216 a and the secondtemperature sensor 216 b are configured to measure the temperature ofthe exhaust gas entering the intake pipe 202, and exiting the intakepipe 202 after flowing through the first catalyst 210, respectively.

The filtration and reduction unit 218 includes a housing 219 defining aninternal volume. The housing 219 can be formed from any suitablematerial, for example, metals or ceramics. Moreover, the housing 219 candefine any suitable cross-section, for example, a circular, square,rectangular, polygonal, elliptical, or any other suitable cross-section.

The filter 220 is disposed within the internal volume defined by thehousing 219. The filter 220 is disposed downstream of the intake pipe202 and upstream of the body mixer 230. The filter 220 is configured toreceive the flow of the exhaust gas (e.g., a diesel exhaust gas) fromthe intake pipe 202. The filter 220 can include any suitable filter(e.g., a diesel particulate filter) configured to filter and remove anyparticulates entrained within the exhaust gas flow, and prevent suchparticulates from entering the SCR system 250. Such particles caninclude, for example, dust, soot, organic particles, crystals, or anyother solid particulates present in the exhaust gas. The filter 220 caninclude a filter housing made of a strong and rigid material such as,for example, high density polypropylene (HDPP) which can define aninternal volume to house a filter element. Any suitable filter elementcan be used such as, for example, a cotton filter element, anacrylonitrile butadiene styrene (ABS) filter element, any other suitablefilter element or a combination thereof. The filter element can have anysuitable pore size, for example, about 10 microns, about 5 microns, orabout 1 micron.

A temperature sensor 226 is disposed proximate to an inlet of the filter220 and configured to measure a temperature of the exhaust gas flowinginto the filter 220. A pressure sensor 222 is positioned across thefilter 220 and can include, for example a differential pressure sensor.The pressure sensor 222 is configured to measure a differential pressureor pressure drop of the exhaust gas flowing across the filter 220. Thepressure sensor 222 can, for example, be used to determine a performanceefficiency or otherwise life remaining of the filter 220. For example, adrop in pressure of the exhaust gas above a predetermined threshold canindicate that the filter 220 is clogged and/or needs replacement.

The body mixer 230 is disposed within the internal volume defined by thehousing 219 downstream of the filter 220 and upstream of the SCR system250, and fluidically couples the filter 220 to the SCR system 250. Thebody mixer 230 can include a body mixer housing defining an internalvolume. An injection port 240 is disposed on a sidewall of the bodymixer 230 and configured to communicate an exhaust reductant into thebody mixer 230. In some embodiments, the exhaust gas can include adiesel exhaust gas and the exhaust reductant can include a dieselexhaust fluid. The diesel exhaust fluid can include, urea, an aqueoussolution of urea, or any other fluid that includes ammonia, by products,or any other diesel exhaust fluid as is known in the arts (e.g., thediesel exhaust fluid marketed under the name ADBLUE®. A temperaturesensor 236 is disposed proximate to an inlet of the body mixer 230. Thetemperature sensor 236 can be configured to measure a temperature of theexhaust gas flowing into the body mixer 230.

The body mixer 230 is structured to allow efficient mixing of theexhaust reductant with the exhaust gas before communicating the exhaustgas into the SCR system 250. The body mixer 230 can include any suitablestructures such as, for example, passageways, bluffs, vanes, partitionwalls, or any other features or structures to facilitate the mixing ofthe reductant with the exhaust gas, increase retention time, increasetemperature, reduce exhaust reductant deposits, and/or reducebackpressure.

The SCR system 250 is disposed within the internal volume defined by thehousing 219 downstream of the body mixer 230 and is configured to treatan exhaust gas (e.g., a diesel exhaust gas) flowing through the SCRsystem 250. The SCR system 250 is configured to selectively reduce aportion of the exhaust gas. For example, the exhaust reductant reactswith the exhaust gas in presence of the catalysts included in the SCRsystem 250 to at least partially reduce one or more components of thegas (e.g., SOx and/or NOx gases), or facilitate reduction of the one ormore components in the presence of one or more catalysts. A temperaturesensor 256 is disposed proximate to an outlet of the SCR system 250. Thetemperature sensor 256 can be configured to measure a temperature of theexhaust gas flowing out of the filtration and reduction unit 218 intothe exhaust pipe 280.

The SCR system 250 includes one or more catalysts formulated toselectively reduce the exhaust gas. Any suitable catalyst can be usedsuch as, for example, platinum, palladium, rhodium, cerium, iron,manganese, copper, vanadium based catalyst, any other suitable catalyst,or a combination thereof. The catalyst can be disposed on a suitablesubstrate such as, for example, a ceramic (e.g., cordierite) or metallic(e.g., kanthal) monolith core which can, for example, define a honeycombstructure. A washcoat can also be used as a carrier material for thecatalysts. Such washcoat materials can include, for example, aluminumoxide, titanium dioxide, silicon dioxide, any other suitable washcoatmaterial, or a combination thereof. The exhaust gas (e.g., dieselexhaust gas) can flow over and about the catalyst such that any SOx orNOx gases included in the exhaust gas are further reduced to yield anexhaust gas which is substantially free of carbon monoxide, SOx and NOxgases.

The exhaust pipe 280 is disposed downstream of the filtration andreduction unit 218. The exhaust pipe 280 can be formed fromsubstantially the same materials as the intake pipe 202. The exhaustpipe 280 is configured to receive the treated exhaust gas (or otherwisemixture of treated exhaust gas and any excess exhaust reductant (e.g.,urea) or its byproducts (e.g., ammonia), and deliver it to the externalenvironment.

The second catalyst 270 is disposed within the exhaust pipe 280. Thesecond catalyst 270 can be configured to oxidize any excess exhaustreductant remaining in the exhaust gas exiting the SCR system 250.

In some embodiments, the exhaust reductant can be a diesel exhaust fluid(e.g., an aqueous solution of urea as described herein) that provides asource of ammonia for participating in the selective catalytic reductionwithin the SCR system 250. In such embodiments, the second catalyst 270can include an ammonium oxidation catalyst formulated to oxidize ammoniato nitrogen. Suitable catalysts can include platinum, palladium,iridium, ruthenium, silver, metal oxides (e.g., Co₃O₄, MnO₂, V₂O₅,etc.), Ni, Fe, and/or Mn supported on Al₂O₃, CuO/Al₂O₃, Fe₂O₃/Al₂O₃,Fe₂O₃/TiO₂, Fe₂O₃/ZrO₂, zeolites (e.g., mordenite, ferrierite,chabazite), any other suitable ammonia oxidation catalyst or acombination thereof.

A temperature sensor 276 is disposed within the exhaust pipe 280 andconfigured to measure a temperature of the exhaust gas exiting theexhaust pipe 280 after flowing through the second catalyst 270.Furthermore, a first gas sensor 272 and a second gas sensor 274 are alsodisposed in the exhaust pipe 280, which can be configured to measure aconcentration of a portion of a gas included in the exhaust gas exitingthe exhaust pipe 280. In some embodiments, the exhaust gas can be adiesel exhaust gas. In such embodiments, the first gas sensor 272 caninclude a NOx sensor and/or a SOx sensor, configured to measure aconcentration of NOx and/or SOx gases included in the exhaust gasexiting the exhaust pipe 280. Moreover, the second gas sensor 274 caninclude an ammonia sensor configured to measure a concentration ofammonia in the exhaust gas (e.g., a breakdown product of a dieselexhaust fluid such as urea).

As described herein, the first catalyst 210 is disposed in the intakepipe 202, and the second catalyst 270 is disposed in the exhaust pipe280. This can enable a dimension (e.g., a length) of the SCR system 250,the body mixer 230, and/or the filter 220 to be increased withoutincreasing the overall dimension (e.g., length) of the filtration andreduction unit 218. In this manner, the filtration and reduction unit218 can provide increased retention time of the exhaust gas, highertemperature of the exhaust gas, more effective removal of NOx and SOxgases from the exhaust gas, and/or reduced backpressure.

FIG. 3 is side cross-section view of another embodiment of anaftertreatment system 300 which can be used for treating an exhaust gas(e.g., a diesel exhaust gas) produced by an IC engine (e.g., a dieselengine). The aftertreatment system 300 includes an intake pipe 302, afirst catalyst 310, a filtration and reduction unit 318 that includes afilter 320, a body mixer 330 and a SCR system 350, a second catalyst370, and an exhaust pipe 380.

The intake pipe 302 is disposed upstream of the filtration and reductionunit 318, and is configured to receive an exhaust gas (e.g., a dieselexhaust gas) from an IC engine (e.g., a diesel engine) and communicatethe exhaust gas to the filtration and reduction unit 318. The intakepipe 302 can be made from a strong, rigid, heat and/or corrosionresistant material such as, metals (e.g., stainless steel, aluminum,alloys, etc.), ceramics, any other suitable material or a combinationthereof. The intake pipe 302 can have any suitable cross-section, forexample, a circular, square, rectangular, polygonal, oval, or any othersuitable cross-section.

The intake pipe 302 divides at a Y joint into a first intake pipe 302 aand a second intake pipe 302 b. The first intake pipe 302 a and thesecond intake pipe 302 b are configured to divide the intake flow ofexhaust gas into a first intake flow and a second intake flow, which aresubsequently communicated to the filtration and reduction unit 318.

The first catalyst 310 is disposed in a first flow path defined by thefirst intake pipe 302 a, and also in a second flow path defined by thesecond intake pipe 302 b. The first catalyst 310 is formulated tooxidize at least a portion of the exhaust gas flowing through the firstintake pipe 302 a and the second intake pipe 302 b. For example, in someembodiments in which the exhaust gas is a diesel exhaust gas, the firstcatalyst 310 can include a diesel oxidation catalyst. The dieseloxidation catalyst can be formulated to oxidize carbon monoxide,hydrocarbons, and/or particulate matter included in the exhaust gasflow. Moreover, the diesel oxidation catalyst can be formulated to havelow light-off temperature and high tolerance to sulfur (e.g., SOx gasesincluded in the exhaust gas). Suitable diesel oxidation catalysts caninclude, for example, platinum, palladium, aluminum oxide, or acombination thereof

A first temperature sensor 316 a is disposed in the first intake pipe302 a upstream of the first catalyst 310, and a second temperaturesensor 316 b is disposed in the first intake pipe 302 a downstream ofthe first catalyst 310. Furthermore, a third temperature sensor 316 c isdisposed in the second intake pipe 302 b upstream of the first catalyst310, and a fourth temperature sensor 316 d is also disposed in thesecond intake pipe 302 b downstream of the first catalyst 310. The firsttemperature sensor 316 a and the second temperature sensor 316 b areconfigured to measure the temperature of the exhaust gas entering thefirst intake pipe 302 a, and exiting the first intake pipe 302 a afterflowing through the first catalyst 310, respectively. Similarly, thethird temperature sensor 316 c and the fourth temperature sensor 316 dare configured to measure the temperature of the exhaust gas enteringthe second intake pipe 302 b, and exiting the second intake pipe 302 bafter flowing through the first catalyst 310, respectively.

While shown as dividing into the first intake pipe 302 a and the secondintake pipe 302 b, the intake pipe 302 can be divided or otherwise splitinto any number of intake pipes for dividing the intake flow of exhaustgas into a plurality of intake flows. Dividing the flow can, forexample, reduce the backpressure of the exhaust gas, or allow moreefficient interaction of the intake flow with the first catalyst 310.

The filtration and reduction unit 318 includes a housing 319 defining aninternal volume. The housing 319 can be substantially similar to thehousing 219 described with respect to the aftertreatment system 200 andtherefore, not described in further detail herein.

The filter 320 is disposed within the internal volume defined by thehousing 319 upstream of the body mixer 330. The filter 320 is configuredto receive the flow of the exhaust gas (e.g., a diesel exhaust gas) fromthe first intake pipe 302 a and the second intake pipe 302 b, andsubstantially remove particulates from the exhaust gas. The filter 320can be substantially similar to the filter 220 described with respect tothe aftertreatment system 200 and therefore, not described in furtherdetail herein.

A temperature sensor 326 is disposed proximate to an inlet of the filter320 and configured to measure a temperature of the exhaust gas flowinginto the filter 320. A pressure sensor 322, for example a differentialpressure sensor, is also disposed across the filter 320. The pressuresensor 322 can be configured to measure a pressure difference of theexhaust gas flowing across the filter 320. The pressure sensor 322 can,for example, be used to determine performance efficiency or otherwiseremaining life of the filter 320. For example, a drop in pressure of theexhaust gas above a predetermined threshold can indicate that the filter320 is clogged and/or needs replacement.

The body mixer 330 is disposed within the internal volume defined by thehousing 319 downstream of the filter 320 and upstream of the SCR system350, and fluidically couples the filter 320 to the SCR system 350. Thebody mixer 230 can include a body mixer housing defining an internalvolume. An injection port 340 is disposed on a sidewall of the bodymixer 330 and configured to communicate an exhaust reductant into thebody mixer 330.

In some embodiments, the exhaust gas can include a diesel exhaust gasand the exhaust reductant can include a diesel exhaust fluid. The dieselexhaust fluid can include urea, an aqueous solution of urea, or anyother fluid that includes ammonia, by products, or any other dieselexhaust fluid as is known in the arts (e.g., the diesel exhaust fluidmarketed under the name ADBLUE®). A temperature sensor 336 is disposedproximate to an inlet of the body mixer 330. The temperature sensor 336can be configured to measure a temperature of the exhaust gas flowinginto the body mixer 330.

The body mixer 330 is structured to allow efficient mixing of theexhaust reductant with the exhaust gas before communicating the exhaustgas into the SCR system 350. The body mixer 330 can include any suitablestructures such as, for example, passageways, bluffs, vanes, partitionwalls, or any other features or structures to facilitate the mixing ofthe reductant with the exhaust gas, increase retention time, increasetemperature, reduce exhaust reductant deposits, and/or reducebackpressure.

The SCR system 350 is disposed within the internal volume defined by thehousing 319 downstream of the body mixer 330 and is configured to treatan exhaust gas (e.g., a diesel exhaust gas) flowing through the SCRsystem 350. The SCR system 350 is configured to selectively reduce aportion of the exhaust gas. The SCR system 350 can be substantiallysimilar to the SCR system 250 described herein with respect to theaftertreatment system 200 and therefore, not described in further detailherein. A temperature sensor 356 is disposed proximate to an outlet ofthe SCR system 350. The temperature sensor 356 can be configured tomeasure a temperature of the exhaust gas flowing out of the SCR systeminto the exhaust pipe 380.

The exhaust pipe 380 is disposed downstream of the filtration andreduction unit 318. The exhaust pipe 380 can be formed fromsubstantially the same materials as the intake pipe 302. The exhaustpipe 380 is configured to receive the treated exhaust gas (or otherwisemixture of treated exhaust gas and any excess exhaust reductant (e.g.,urea) or its byproducts (e.g., ammonia), and deliver it to the externalenvironment. The second catalyst 370 is disposed within the exhaust pipe380. The second catalyst 370 can be configured to oxidize any excessexhaust reductant remaining in the exhaust gas exiting the SCR system350.

In some embodiments, the exhaust reductant can be a diesel exhaust fluid(e.g., an aqueous solution of urea as described herein) that provides asource of ammonia for participating in the selective catalytic reductionwithin the SCR system 350. In such embodiments, the second catalyst 370can include an ammonium oxidation catalyst formulated to oxidize ammoniato nitrogen, as described herein with respect to the second catalyst 270included in the aftertreatment system 200.

A temperature sensor 376 is disposed within the intake pipe 302 and isconfigured to measure a temperature of the exhaust gas exiting theexhaust pipe 380 after flowing through the second catalyst 370.Furthermore, a first gas sensor 372, and a second gas sensor 374 arealso disposed in the exhaust pipe 380, and can be configured to measurea concentration of a portion of a gas included in the exhaust gasexiting the exhaust pipe 380. In some embodiment, the exhaust gas can bea diesel exhaust gas. In such embodiments, the first gas sensor 372 caninclude a NOx sensor and/or a SOx sensor, configured to measure aconcentration of NOx and/or SOx gases included in the exhaust gasexiting the exhaust pipe 380. Moreover, the second gas sensor 374 caninclude an ammonia sensor configured to measure a concentration ofammonia in the exhaust gas (e.g., a breakdown product of a dieselexhaust fluid such as urea).

In some embodiments, a portion of the exhaust pipe 380 proximate to thefiltration and reduction unit 318 can also be divided or otherwise splitinto a plurality of exhaust pipes. For example, two, three or even moreexhaust pipes can be coupled to an outlet of the filtration andreduction unit 318, and configured to receive a portion of the treatedexhaust gas from the SCR system 350. The plurality of exhaust pipes canthen merge together at the exhaust pipe 380. In such embodiments, secondcatalyst 370 can be disposed in each of the plurality of exhaust pipes.

FIG. 4 is a schematic flow diagram of an example method 400 forincreasing a space available within an internal volume defined by ahousing (e.g., the housing 219/319) of an aftertreatment system (e.g.,the aftertreatment system 100/200/300). The larger space availablewithin the internal volume defined by the housing allows increase indimensions of a SCR system (e.g., the SCR system 150/250/350), a filter(e.g., the filter 120/220/320) and/or a body mixer (e.g., the body mixer(e.g., the body mixer 230/330) positionable within the internal volumedefined by the housing 219/319 or any other housing described herein.

The method 400 includes positioning an SCR system within the internalvolume of the housing at 402. For example, the SCR system 150/250/350 orotherwise a SCR catalyst is positioned within the internal volumedefined by the housing 219/319 or any other housing described herein. Insome embodiments, a filter is positioned upstream of the SCR systemwithin the internal defined by the housing at 404. For example, thefilter 120/220/320 is positioned upstream of the SCR system within theinternal volume of the housing 219/319 or any other housing describedherein so that the filter 120/220/320 is positioned proximate to theinlet and the SCR system is positioned proximate to an outlet of thehousing 219/319 or any other housing described herein. In particularembodiments, the method 400 can also include positioning a differentialpressure sensor (e.g., the differential pressure sensor 222/322) acrossthe filter 120/220/320.

In particular embodiments, a body mixer is positioned upstream of theSCR system and downstream of the filter within the internal volumedefined by the housing at 406. For example, the body mixer 230/330 ispositioned between the filter 120/220/320 and the SCR system 150/250/350within the internal volume of the housing 219/319 or any other housingdescribed herein. The body mixer 230/330 can be structured to receive areductant, for example via an insertion unit (e.g. a reductant injector)fluidly coupled to the housing 219/319 or any other housing describedherein, and facilitate mixing of the reductant with an exhaust gas(e.g., a diesel exhaust gas) flowing through the aftertreatment system100/200/300.

An intake pipe is fluidly coupled to an inlet of the housing at 408. Forexample, the intake pipe 102/202/302 is fluidly coupled to an inlet ofthe housing 219/319 or any other housing described herein. A firstcatalyst is positioned within the intake pipe at 410. For example, thefirst catalyst 110/210/310 is positioned within the intake pipe102/202/302. In particular embodiments, the intake pipe (e.g., theintake pipe 302) may be divided into a plurality of intake pipes fluidlycoupled to the inlet of the housing 219/319 or any other housingdescribed herein. In such embodiments, the first catalyst 110/210/310 ispositioned within each of the plurality of intake pipes. In someembodiments, the first catalyst 110/210/310 includes a diesel oxidationcatalyst, as described herein.

In some embodiments, the method 400 also includes coupling an exhaustpipe to an outlet of the housing at 412. For example, the exhaust pipe180/280/380 is coupled to an outlet of the housing 219/319 or any otherhousing described herein. A second catalyst may be positioned within theexhaust pipe at 414. For example, the second catalyst 170/270/370 may bepositioned within the exhaust pipe 180/280/380. In various embodiments,the second catalyst 170/270/370 includes an ammonia oxidation catalyst.

As used herein, the singular forms “a”, “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, the term “a member” is intended to mean a single member or acombination of members, “a material” is intended to mean one or morematerials, or a combination thereof.

It should be noted that the term “exemplary” or “example” as used hereinto describe various embodiments is intended to indicate that suchembodiments are possible examples, representations, and/or illustrationsof possible embodiments (and such term is not intended to connote thatsuch embodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

It is important to note that the construction and arrangement of thevarious exemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Othersubstitutions, modifications, changes and omissions may also be made inthe design, operating conditions and arrangement of the variousexemplary embodiments without departing from the scope of the presentinvention.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular implementations of particularinventions. Certain features described in this specification in thecontext of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresdescribed in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variations of a subcombination.

What is claimed is:
 1. An aftertreatment system, comprising: a housingincluding an inlet, an outlet and defining an internal volume; an intakepipe disposed upstream of the housing and fluidly coupled to the inlet,and a downstream portion of the intake pipe dividing into a plurality ofintake pipes, a downstream end of each of the plurality of intake pipescoupled to the housing; a selective catalytic reduction systempositioned within the internal volume defined by the housing; and aplurality of first catalysts formulated to oxidize at least a portion ofthe exhaust gas, each of the first catalysts disposed in a respectiveone of the plurality of intake pipes.
 2. The aftertreatment system ofclaim 1, further comprising: a filter positioned within the internalvolume defined by the housing, the filter positioned upstream of theselective catalytic reduction system.
 3. The aftertreatment system ofclaim 2, further comprising: a body mixer positioned downstream of thefilter and upstream of the selective catalytic reduction system withinthe internal volume defined by the housing, the body mixer structured tomix a reductant with an exhaust gas flowing through the aftertreatmentsystem.
 4. The aftertreatment system of claim 2, further comprising adifferential pressure sensor positioned across the filter.
 5. Theaftertreatment system of claim 1, wherein the first catalyst comprises adiesel oxidation catalyst.
 6. The aftertreatment system of claim 1,further comprising: an exhaust pipe fluidly coupled to the outlet of thehousing; and a second catalyst positioned within the exhaust pipe. 7.The aftertreatment system of claim 6, wherein the second catalystcomprises an ammonia oxidation catalyst.
 8. The aftertreatment system ofclaim 7, wherein at least one of a NOx sensor and an ammonia sensor areoperatively coupled to the exhaust pipe downstream of the secondcatalyst.
 9. The aftertreatment system of claim 1, wherein each of thefirst catalyst has a first radial cross-sectional dimension that issmaller than a second radial cross-sectional dimension of the housing.10. The aftertreatment system of claim 1, wherein the upstream portionof the intake pipe has a first radial cross-sectional dimension, thehousing has a second radial cross-sectional dimension that is largerthan the first radial cross-sectional dimension, and a radialcross-sectional dimension of the aftertreatment system consistentlyincreases in a downstream direction from the first radialcross-sectional dimension to the second radial cross-sectionaldimension.
 11. The aftertreatment system of claim 1, wherein each of thefirst catalyst is removably positioned within the respective intake pipeso as to allow removal of the first catalyst from the respective intakepipe without removing the intake pipe from the aftertreatment system.12. The aftertreatment system of claim 1, further comprising: a firsttemperature sensor disposed in each of the plurality of intake pipesupstream of each of the first catalyst; and a second temperature sensordisposed in each of the plurality of intake pipes downstream of each ofthe first catalyst.
 13. The aftertreatment system of claim 1, wherein:each of the first catalyst has an upstream end that is downstream of anupstream end of the respective one of the plurality of intake pipes, andeach of the first catalyst has a downstream end that is upstream of adownstream end of the respective one of the plurality of intake pipesthat is coupled to the inlet of the housing.